Currently, all micro-controller integrated circuits (ICs) require a reference clock frequency. Typically, the reference clock frequency is generated by a crystal oscillator. The crystal is usually large in comparison to the IC size. The crystal size limits the IC package design and implementation. Although crystals may be used to produce an accurate reference clock frequency, crystals are relatively expensive compared to the cost of IC silicon.
It would be desirable to have a cost effective integrated circuit and a method for generating an accurate clock reference for the integrated circuit, wherein the integrated circuit is calibrated without the use of a crystal.